Fuel Rumor

:devil I HAVE HEARD THAT YOU CAN RUN "VP FUEL " IN THE 400EX IS THIS RUMOR TRUE.IF NOT WHAT IS A SAFE OCTANE RATING.

We use 76 VP race fuel in our Quads. It's 110 octane. We actualy run 50/50 mix (110/92) octane for cost efficency when playridding. Then when we race we use 110 only. Our motors have had work done and are 11.1 comp ratio. If you are running a stock Quad then 92 will be fine. Unless you wan to spend 4.00 a gallon on race fuel.

Hope this helps.

I just love the smell !!!

Race fuel will do nothing for a stock motor,,so don't waste your money,,just run the highest octane they sell at the local gas station.

[JabberJaw]

2001 400ex W/bearded fenders, plastic flywheel, paper airbox. Extended Fisher Price Racing A-arms, Red Rubber Brake Lines. Tonka case saver, Rubberband steering dampner, perch for the parrot & lever 2000, Used E-brake blockoff, Rubbermaid axlenut. Auqu header, Mopar powercore, Wooden handle bars. Paperclip racing handlebar clamp, pantyhose headlight covers, & paper number plates. AC/DC racing front bumper, fiberglass swingarm skid, full body wine dispencer, & propeller nerfs. Sponge for air filter, black neoprene hood cover. Ceramic eliminator axle. Dimsum triple rate shocks W/rezzy, Tupperware black gas tank cover, stripped wire kill switch & ammco power shifter, Sandpaper seat cover, Styrofoam resevior cover, Gas petrock, Rear master bater guard, seat launch & head cover, Chrome tires and rear brake pedestal, Custom oil retainer scoops, Tyson hand guards, Dynomite kit, XR50 cam, JE 16 piston(1.8:1), Douglas Fir .19 race rims W/knockoffs, hole**** BMX tires all around

[JOEX]

If you ain't broke,,then you ain't high enough.

You guys got too much time on your hands...nice mod list jabber.. LMAO

[JabberJaw]

It's a nice bike! Hehhehehe

[papaw]

hey zooter,have you tried anything lower than 50/50 on your 11:1 piston?i ran 110 all last summer,and have since found out that any modded motor or stock motor for that matter needs the lowest octane possible (without detonating or pinging)to get the best power out of a motor.somebody correct me if i'm wrong.just trying to get some ideas on what the lowest octane rating for an 11:1 piston.

Well it's true you should run the lowest octane fuel without pinging. The only thing about this statemnet is, it was intended for cars and trucks. In a car or truck you are consuming a lot of fuel over a peroid of time. So for cost effectivenest you should run lowest octane for cost effictivenes. Your car/truck is also liqiud cooled too. So running race fuel to lower combustion temps is not a factor. On a atv that is air or even liquid cooled it is more importaint to run better fuels for cooling effiency. Plus your not buring 1000 gals of fuel a year in your quad (some of us do) so the cost factor doesent play a part. Grannted you will have better fuel econemy using a low octane fuel that burns 100% (no internal combustion engine is 100% efficent) of what you put in. On race fuel you may only burn 90% and the other 10% helps cool things down a little.
It's all super confusing, If you have an modified ATV/ATC/whatever with a higher comp piston you should always check with the manufactor and see what they say. Everbody has a different opion on this topic. I run 50/50 playing because of the higher comp and it helps slighly to cool things down. When I race I use 100% VP 110. I cant realy tell a differance in running but who want to take a chance? Only 4.00$ a gallon and You only need 2 to race.

That's ny two cents worth.

[thorspapa]

Rule of thumb for octane on different compression setups.

Air-cooled engines 125cc - 450cc - up to 10.5:1, premium pump fuel. 10.75:1 to 11.75:1, mix race and pump 1/2 and 1/2. 13:1 and higher, race fuel or alcohol.

Water-cooled 125cc - 450cc - up to 11.5:1 (12:1 on some engines), pump fuel. Anything higher, race gas.

Smaller engines can deal with higher compression without detonation (less surface area). Really big bore engines (like an XR600) won't deal with compression well at all, and will require higher octane fuel than the compression ratio would seem to necessitate.

For the 250Rs, if you're looking at over 180psi readings, you'd be better to use 95 or more octane, chances are you have detonation and don't know it.

I'm not going to say this is straight out of "The Book of Truth", but it's worked well for myself and many others. It's also a guideline given by Powroll.

Disclaimer: If this doesn't work for 'ya, don't sue me, I have no money anyway